Especially with regard to children's shoes, there is a considerable risk that the feet of a toddler will deform if he wears the wrong size of children's shoe, thereby leading to possible permanent posture injury. In view of this, the main problem is that shoes of various manufacturers can have different inner shoe measurements in spite of indicating the same shoe size.
Moreover, errors are often made while children's feet are being measured because an accurate measurement can only be properly made when the foot is being strained. Another problem is that shoes expand after being worn a while and this changes their inner measurements. Furthermore, a child's foot measurements change a great deal, especially during growth spurts. For these reasons, it is essential for the healthy and normal development of children's feet that the shoes currently being worn and the actual foot size are measured again on a regular basis for comparison purposes.
However, wearing the wrong shoe size is not only detrimental to children, but to adults as well. In fact, many foot diseases are associated with wearing shoes that are too narrow, and this affects one's well-being for a long time.
The measuring gadgets for the inner shoe known to date merely consider a fixed growth space of 12 mm. However, these gadgets are very cumbersome and can only determine exact measurements unreliably and inaccurately.
A precision instrument for measuring foot length and the inner shoe is known from DE 20 2011 103 464 U1. It comprises a basic part and a movable measuring gadget, as well as a likewise movable precision measuring instrument located in the front part of the measuring gadget. This very handy gadget records first of all the length of a foot that is under strain, positioned inside the shoe-measuring gadget. Afterwards, the gadget is inserted in a shoe to be measured. The precision measuring instrument arranged in the front part of the measuring gadget determines the remaining spatial length between the longest toe of the foot and the inner shoe wall in front of this toe. The gadget has the advantage of being very small and handy—and can therefore be conveniently taken along when buying shoes. In addition, it allows the measurement of shoes at home. Furthermore, the remaining foot-moving space can be measured very reliably. The disadvantage, however, is that this gadget does not measure the width, so it is possible for someone to wear a shoe that fits very well longitudinally but is too narrow or wide. As a result of this, posture problems and foot diseases can occur, in addition to affecting well-being for a long time.